//! TDD Tests for Trading Agent Monitoring Module
//!
//! Testing Strategy:
//! 1. Metrics initialization and registration
//! 2. Recording operations (universe, assets, allocation, orders)
//! 3. Error tracking
//! 4. Prometheus export
//!
//! Status: TDD - Tests written FIRST

use prometheus::{Encoder, TextEncoder};
use trading_agent_service::monitoring::TradingAgentMetrics;

#[test]
fn test_metrics_initialization() {
    // Test that metrics can be created without panicking
    let metrics = TradingAgentMetrics::new();

    // Verify metrics object is valid
    // Note: All values >= 0, so this just ensures metrics exists
    let _ = std::mem::size_of_val(&metrics);

    // Basic smoke test - should not panic
    let _ = metrics;
}

#[test]
fn test_record_universe_selection() {
    let metrics = TradingAgentMetrics::new();

    // Record a universe selection operation
    metrics.record_universe_selection(125.5, 150);

    // Record multiple operations to test counter increments
    metrics.record_universe_selection(98.2, 140);
    metrics.record_universe_selection(201.3, 165);

    // Verify no panics occurred
}

#[test]
fn test_record_asset_selection() {
    let metrics = TradingAgentMetrics::new();

    // Record asset selection operations
    metrics.record_asset_selection(45.2, 25);
    metrics.record_asset_selection(52.8, 30);
    metrics.record_asset_selection(38.1, 20);

    // Verify no panics occurred
}

#[test]
fn test_record_allocation() {
    let metrics = TradingAgentMetrics::new();

    // Record portfolio allocation operations
    metrics.record_allocation(78.5, 1_000_000.0);
    metrics.record_allocation(92.1, 1_250_000.0);
    metrics.record_allocation(65.3, 980_000.0);

    // Verify no panics occurred
}

#[test]
fn test_record_order_generation() {
    let metrics = TradingAgentMetrics::new();

    // Record order generation operations
    metrics.record_order_generation(12.4, 5);
    metrics.record_order_generation(18.9, 8);
    metrics.record_order_generation(9.2, 3);

    // Verify no panics occurred
}

#[test]
fn test_record_error() {
    let metrics = TradingAgentMetrics::new();

    // Record various error types
    metrics.record_error("universe_selection_failed");
    metrics.record_error("asset_selection_timeout");
    metrics.record_error("allocation_constraint_violation");
    metrics.record_error("order_generation_failed");
    metrics.record_error("database_connection_error");

    // Verify no panics occurred
}

#[test]
fn test_metrics_export() {
    let metrics = TradingAgentMetrics::new();

    // Record various operations
    metrics.record_universe_selection(100.0, 150);
    metrics.record_asset_selection(50.0, 25);
    metrics.record_allocation(75.0, 1_000_000.0);
    metrics.record_order_generation(10.0, 5);
    metrics.record_error("test_error");

    // Export metrics to Prometheus text format
    let encoder = TextEncoder::new();
    let metric_families = prometheus::gather();
    let mut buffer = vec![];
    encoder.encode(&metric_families, &mut buffer).unwrap();

    let output = String::from_utf8(buffer).expect("INVARIANT: Valid UTF-8 bytes");

    // Verify key metrics are present in output
    assert!(output.contains("trading_agent"));

    // Verify specific metric names exist (if they follow naming conventions)
    // Note: Actual metric names depend on implementation
}

#[test]
fn test_concurrent_metric_recording() {
    use std::sync::Arc;
    use std::thread;

    let metrics = Arc::new(TradingAgentMetrics::new());

    let mut handles = vec![];

    // Spawn multiple threads recording metrics concurrently
    for i in 0..10 {
        let metrics_clone = Arc::clone(&metrics);
        let handle = thread::spawn(move || {
            for j in 0..100 {
                let duration = (i * 100 + j) as f64;
                metrics_clone.record_universe_selection(duration, i * 10 + j);
                metrics_clone.record_asset_selection(duration / 2.0, i * 5 + j);
                metrics_clone.record_allocation(duration * 1.5, (i * 100000 + j * 1000) as f64);
                metrics_clone.record_order_generation(duration / 10.0, i + j);
            }
        });
        handles.push(handle);
    }

    // Wait for all threads to complete
    for handle in handles {
        handle.join().expect("INVARIANT: Thread should complete successfully");
    }

    // Verify no panics or data races occurred
}

#[test]
fn test_histogram_buckets() {
    let metrics = TradingAgentMetrics::new();

    // Test various duration values to ensure histogram buckets work
    let test_durations = vec![
        0.001,  // 1μs
        0.01,   // 10μs
        0.1,    // 100μs
        1.0,    // 1ms
        10.0,   // 10ms
        100.0,  // 100ms
        1000.0, // 1s
        5000.0, // 5s
    ];

    for duration in test_durations {
        metrics.record_universe_selection(duration, 100);
        metrics.record_asset_selection(duration, 50);
        metrics.record_allocation(duration, 1_000_000.0);
        metrics.record_order_generation(duration, 5);
    }

    // Verify no panics occurred
}

#[test]
fn test_gauge_updates() {
    let metrics = TradingAgentMetrics::new();

    // Test that gauges update correctly (not just increment)
    metrics.record_universe_selection(100.0, 150);
    metrics.record_universe_selection(100.0, 200); // Should update gauge to 200
    metrics.record_universe_selection(100.0, 100); // Should update gauge to 100

    metrics.record_asset_selection(50.0, 25);
    metrics.record_asset_selection(50.0, 50); // Should update gauge to 50

    metrics.record_allocation(75.0, 1_000_000.0);
    metrics.record_allocation(75.0, 2_000_000.0); // Should update gauge to 2M

    // Verify no panics occurred
}

#[test]
fn test_zero_values() {
    let metrics = TradingAgentMetrics::new();

    // Test edge case with zero values
    metrics.record_universe_selection(0.0, 0);
    metrics.record_asset_selection(0.0, 0);
    metrics.record_allocation(0.0, 0.0);
    metrics.record_order_generation(0.0, 0);

    // Verify no panics occurred
}

#[test]
fn test_large_values() {
    let metrics = TradingAgentMetrics::new();

    // Test edge case with large values
    metrics.record_universe_selection(99999.0, u64::MAX);
    metrics.record_asset_selection(99999.0, u64::MAX);
    metrics.record_allocation(99999.0, f64::MAX / 2.0); // Avoid overflow
    metrics.record_order_generation(99999.0, u64::MAX);

    // Verify no panics occurred
}

#[test]
fn test_error_type_variety() {
    let metrics = TradingAgentMetrics::new();

    // Test various error type strings
    let error_types = vec![
        "timeout",
        "database_error",
        "validation_failed",
        "resource_exhausted",
        "permission_denied",
        "internal_error",
        "network_failure",
        "constraint_violation",
    ];

    for error_type in error_types {
        metrics.record_error(error_type);
    }

    // Test edge cases separately
    metrics.record_error(""); // Empty string edge case
    let long_string = "a".repeat(256);
    metrics.record_error(&long_string); // Long string edge case

    // Verify no panics occurred
}

#[test]
fn test_metrics_independence() {
    // Create multiple independent metrics instances
    let metrics1 = TradingAgentMetrics::new();
    let metrics2 = TradingAgentMetrics::new();

    // Record to first instance
    metrics1.record_universe_selection(100.0, 150);
    metrics1.record_error("error1");

    // Record to second instance
    metrics2.record_asset_selection(50.0, 25);
    metrics2.record_error("error2");

    // Both should work independently without interference
    // Note: In practice, Prometheus metrics are global, but instances should be safe to create
}

#[test]
fn test_realistic_workflow() {
    let metrics = TradingAgentMetrics::new();

    // Simulate a realistic trading agent workflow

    // 1. Universe selection
    metrics.record_universe_selection(125.5, 150);

    // 2. Asset selection (subset of universe)
    metrics.record_asset_selection(45.2, 25);

    // 3. Portfolio allocation
    metrics.record_allocation(78.5, 1_000_000.0);

    // 4. Order generation
    metrics.record_order_generation(12.4, 5);

    // 5. Another cycle
    metrics.record_universe_selection(135.2, 145);
    metrics.record_asset_selection(48.9, 28);
    metrics.record_allocation(82.1, 1_050_000.0);
    metrics.record_order_generation(15.7, 6);

    // 6. Error occurs
    metrics.record_error("market_data_stale");

    // Verify complete workflow executes without panics
}

#[test]
fn test_metrics_after_error() {
    let metrics = TradingAgentMetrics::new();

    // Record normal operations
    metrics.record_universe_selection(100.0, 150);

    // Record error
    metrics.record_error("test_error");

    // Verify metrics can still be recorded after error
    metrics.record_asset_selection(50.0, 25);
    metrics.record_allocation(75.0, 1_000_000.0);
    metrics.record_order_generation(10.0, 5);

    // Another error
    metrics.record_error("another_error");

    // Continue recording
    metrics.record_universe_selection(110.0, 160);

    // Verify no panics occurred
}